In the six months to December, RWE's net profit grew by 15.2 per cent to 369 million euros ($406 million), largely as a result of consolidation changes and other one-off factors.

"We are confident that we will be able to meet our goal of a 10 per cent increase in profits this year," RWE said in a statement.

In the first half, group sales fell by 2.4 per cent to 18.369 billion euros ($20.2 billion). This was largely owing to a decline in revenues in the oil and chemicals businesses as a result of lower oil prices. But divestments and declining sales volumes in the mining and raw materials divisions also ate into sales, RWE said.

On the plus side, acquisitions in the environmental services and machine construction divisions had a positive effect on turnover.

Adjusted for these various factors, internal growthstood at 1.8 per cent, the statement said.

Domestic sales, which account for two thirds of overall business, fell as much as 3.0 per cent to 14.372 billion euros ($15.8 billion), while overseas business slipped by only 0.2 per cent to 3.997 billion euros ($4.4 billion).RWE said it would offer to buy out the outstanding shares in its Lahmeyer unit at 47 euros per share ($52), bringing the total transaction to 1.5 billion euros ($1.7 billion).

Insurance giant Allianz has already agreed to sell its stake, which means RWE already controls more than 80 per cent in Lahmeyer, the company said.